Touch screen display systems, or “touch screens,” are increasingly relied upon as user input devices because they offer a variety of benefits. One benefit is a reduction in space; generally, a series of separate mechanical buttons or switches takes up more space than the same number of touch targets, or buttons, when consolidated into a touch screen display system. The reduced space results in a minimization of the scan area that a user must view to locate buttons, which, in turn, decreases the user's cognitive workload. Employing a touch screen display system also typically reduces the number of parts and the assembly time for a given design. Accordingly, user interface designs increasingly rely on touch screen display systems.
In spite of the significant benefits provided by touch screen display systems, emergency and/or critical touch targets (hereinafter referred to as critical buttons) continue to be implemented as mechanical levers or switches to address several concerns. A first concern driving the separate mechanical implementation of a critical button is that it must be quickly and intuitively recognized as a critical button in the context of the application, and with respect to all non-critical buttons available to the user. In practice, the critical button is typically distinguished using visually distinguishing colors, a unique design, a unique location, and may even have a cover placed over it.
Another concern driving the separate mechanical implementation of critical buttons is the need to guard them from unintentional activation. Guarding is generally accomplished by implementing a multi-step process, wherein two or more steps are required to achieve activation of the critical button. In practice, the first step may be flipping open or breaking a cover, and the second step may be manipulating the underlying mechanical lever or switch. It is readily apparent, therefore, that integrating critical buttons into touch screen display systems requires assuring that a user recognizes the critical nature of a critical button and providing a reliable guarding procedure that prevents unintentional activation of the critical button.
Accordingly, a touch screen display system and method that (1) renders a critical button in a visually distinguishable manner, and (2) provides an intuitive multi-step activation process that effectively guards the critical button from unintentional activation is desirable.